code: def lstm_keras_fn(lstm_size):
      return tf.keras.layers.LSTM(
          lstm_size, return_state=True, return_sequences=True
      )
  
file_path: agents/tf_agents/networks/actor_distribution_rnn_network_test.py
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from absl.testing import parameterized
  import tensorflow
  from tf_agents.networks import actor_distribution_rnn_network
  from tf_agents.policies import actor_policy
  from tf_agents.specs import tensor_spec
  from tf_agents.trajectories import time_step
label_desc: Use image node_id 1 for calling a global function with example usage: lstm_keras_fn(lstm_size) and returns: tf